class_docstr: `USPS <https://www.csie.ntu.edu.tw/~cjlin/libsvmtools/datasets/multiclass.html#usps>`_ Dataset.
  The data-format is : [label [index:value ]*256 \n] * num_lines, where ``label`` lies in ``[1, 10]``.
  The value for each pixel lies in ``[-1, 1]``. Here we transform the ``label`` into ``[0, 9]``
  and make pixel values in ``[0, 255]``.
  
  Args:
      root (string): Root directory of dataset to store``USPS`` data files.
      train (bool, optional): If True, creates dataset from ``usps.bz2``,
          otherwise from ``usps.t.bz2``.
      transform (callable, optional): A function/transform that takes in a PIL image
          and returns a transformed version. E.g, ``transforms.RandomCrop``
      target_transform (callable, optional): A function/transform that takes in the
          target and transforms it.
      download (bool, optional): If true, downloads the dataset from the internet and
          puts it in root directory. If dataset is already downloaded, it is not
          downloaded again.
code: def __len__(self) -> int:
      return len(self.data)
  
file_path: vision/torchvision/datasets/usps.py
imports: import os
  from typing import Any, Callable, Optional, Tuple
  import numpy
  from PIL import Image
  from .utils import download_url
  from .vision import VisionDataset
label_desc: Use image node_id 3 for calling the USPS obj's underlying member method code with example usage: obj.__len__() and returns: len